The invention relates to a method and an apparatus for detecting stagnant drinking water.
Stagnant water is to be understood as water which is stationary for a certain period of time in a pipe section. Stagnant water occurs when water is not removed (drawn off) for more than a certain period of time.
After only a few hours the formation of a biofilm can occur in stagnant water as a result of chemical, physical and microbial processes on the inner surface of the pipe section in question. Microbes, which multiply in a biofilm, reach the consumer when water is removed. A health risk to the consumer can result from this.
Pipe sections of e.g. faucets, conduits, shower hoses and tap outlets are affected by microbial contamination. In order to prevent or reduce microbial contamination in pipe sections, ring mains are known from the prior art from which relatively short feed lines go off to the water removal points. The advantage of such a construction is that when drawing off from each water removal point the water in the ring main is moved so that the residence time of the water in the ring main is low and stagnant water occurs only in the relatively short feed lines. The latter is vented by a flushing process before the drinking water (from the ring main) can be used. Ring mains are expensive and cannot be implemented universally.
Precautions can also be taken as regards materials which reduce microbial formation. In particular, materials are known from the prior art which reduce the risk of the formation of a biofilm.
The risk of using microbially contaminated drinking water can basically be reduced by allowing the water to run for a time before drawing off the drinking water provided for use.
The pipe is thus flushed and potentially stagnant water discharged. Depending on the length of the water supply pipe, the running time of the water is up to a few minutes.
The method described above has proved in practice to be satisfactory. However, discharging unused water for a long period of time is environmentally unfriendly, particularly if, for reasons of safety, the water is discharged for longer than would actually be necessary.
Practice shows also that it is frequently not clear before using a drinking water tap connection whether the backed up water is stagnant water or not. The consumer frequently provides security by basically allowing the water to run for a relatively long period of time, regardless of the degree of stagnation of the water, before it is drawn off for its actual use. The result is unnecessary water wastage.
This is where the invention comes into play.
It is the object of the invention to detect stagnant water whilst simultaneously reducing unnecessary water consumption.